monfront - add basic interface to create some entities

1 files changed, 148 insertions, 0 deletions

diff --git a/cmd/monfront/create.go b/cmd/monfront/create.go
new file mode 100644
index 0000000..43805a1
--- /dev/null
+++ b/cmd/monfront/create.go
@@ -0,0 +1,148 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"net/http"
+	"strings"
+)
+
+func showCreate(con *Context) {
+	if con.r.Method == "POST" {
+		addCreate(con)
+		return
+	}
+	if con.r.Method != "GET" {
+		con.w.WriteHeader(http.StatusMethodNotAllowed)
+		con.w.Write([]byte("method is not supported"))
+		return
+	}
+	if !con.CanEdit {
+		con.w.WriteHeader(http.StatusForbidden)
+		con.w.Write([]byte("no permission to change data"))
+		return
+	}
+	con.Content = map[string]any{}
+
+	primitives := []struct {
+		name  string
+		query string
+	}{
+		{"commands", "select id, name, updated, command, message from commands order by name"},
+		{"checkers", "select id, name, description from checkers order by name"},
+		{"notifier", "select id, name, settings from notifier order by name"},
+		{"nodes", "select id, name, updated, message from nodes order by name"},
+	}
+	for _, prim := range primitives {
+		rows, err := DB.Query(prim.query)
+		defer rows.Close()
+		if err != nil {
+			log.Printf("could not get commands: %s", err)
+			con.Error = "could not get commands"
+			returnError(http.StatusInternalServerError, con, con.w)
+			return
+		}
+		result, err := rowsToResult(rows)
+		if err != nil {
+			log.Printf("could not get %s: %s", prim.name, err)
+			con.Error = "could not get " + prim.name
+			returnError(http.StatusInternalServerError, con, con.w)
+			return
+		}
+		con.Content[prim.name] = result
+	}
+
+	con.w.Header()["Content-Type"] = []string{"text/html"}
+	con.Render("create_index")
+	return
+}
+
+type (
+	sqlResult struct {
+		Columns []string
+		Rows    [][]sql.NullString
+	}
+)
+
+func rowsToResult(rows *sql.Rows) (*sqlResult, error) {
+	res := &sqlResult{}
+	cols, err := rows.Columns()
+	if err != nil {
+		return res, fmt.Errorf("could not get columns: %w", err)
+	}
+	res.Columns = cols
+	res.Rows = [][]sql.NullString{}
+	colNum := len(cols)
+
+	for rows.Next() {
+		line := make([]sql.NullString, colNum)
+		lineMap := make([]any, colNum)
+		for i := 0; i < colNum; i++ {
+			lineMap[i] = &(line[i])
+		}
+		if err := rows.Scan(lineMap...); err != nil {
+			return res, fmt.Errorf("could not scan values: %w", err)
+		}
+		res.Rows = append(res.Rows, line)
+	}
+
+	return res, nil
+}
+
+func addCreate(con *Context) {
+	if !con.CanEdit {
+		con.w.WriteHeader(http.StatusForbidden)
+		con.w.Write([]byte("no permission to change data"))
+		return
+	}
+
+	if err := con.r.ParseForm(); err != nil {
+		con.w.WriteHeader(http.StatusBadRequest)
+		fmt.Fprintf(con.w, "could not parse parameters: %s", err)
+		return
+	}
+
+	con.w.Header()["Location"] = []string{"/create"}
+
+	addType := con.r.PostForm.Get("type")
+	types := map[string]struct {
+		Fields []string
+		Table  string
+	}{
+		"command":  {[]string{"name", "command", "message"}, "commands"},
+		"node":     {[]string{"name", "message"}, "nodes"},
+		"checker":  {[]string{"name", "description"}, "checkers"},
+		"notifier": {[]string{"name", "settings"}, "notifier"},
+		"check":    {[]string{"name", "message", "options", "intval", "node_id", "command_id", "checker_id"}, "checks"},
+	}
+	t, found := types[addType]
+	if !found {
+		con.Error = "undefined type '" + addType + "'"
+		returnError(http.StatusBadRequest, con, con.w)
+		return
+	}
+
+	fields := make([]any, len(t.Fields))
+	vals := make([]string, len(t.Fields))
+	for i := 0; i < len(fields); i++ {
+		vals[i] = fmt.Sprintf(`$%d`, i+1)
+		fields[i] = con.r.PostForm.Get(t.Fields[i])
+		if fields[i] == "" {
+			con.Error = "field " + t.Fields[i] + " must not be empty"
+			returnError(http.StatusBadRequest, con, con.w)
+			return
+		}
+	}
+	stmt := `insert into ` + t.Table + `(` + strings.Join(t.Fields, ",") + `) values (` + strings.Join(vals, ",") + `)`
+	_, err := DB.Exec(stmt, fields...)
+	if err != nil {
+		log.Printf("could not insert new %s: %s", addType, err)
+		con.Error = "could not insert new " + addType
+		returnError(http.StatusInternalServerError, con, con.w)
+		return
+	}
+
+	con.w.WriteHeader(http.StatusSeeOther)
+	return
+}